A runny nose during physical activity is a common experience. It affects many people, from casual walkers to seasoned athletes. Understanding why it happens can help demystify this frequent occurrence.
The Body’s Natural Response to Exercise
Physical exertion prompts increased blood circulation throughout the body, including to the delicate tissues lining the nasal passages. This heightened blood flow causes the small blood vessels within the nose to dilate, leading to swelling of the nasal membranes.
As these blood vessels expand and nasal tissues swell, they can become more permeable. This allows fluid to leak from capillaries into surrounding tissue, contributing to the runny sensation. The nasal lining also increases mucus production. This mucus helps humidify and filter air entering the lungs, a process more pronounced during deeper, faster breathing.
Environmental Factors at Play
External conditions often amplify the body’s response. Cold, dry air can irritate sensitive nasal passages. As the body attempts to warm and humidify inhaled air before it reaches the lungs, nasal membranes work harder, increasing mucus secretion. This ensures the lungs receive air at a suitable temperature and humidity.
Low humidity can also dry out nasal mucous membranes. When dry, they produce more mucus to rehydrate and protect themselves. Outdoor exercise exposes individuals to airborne irritants and allergens like pollen, dust, air pollution, or pet dander. These can trigger an inflammatory response in nasal passages, increasing mucus production and causing a runny nose.
When to Be Concerned
While a runny nose during exercise is often normal, it’s helpful to distinguish it from other conditions. If symptoms like itching, sneezing, or watery eyes accompany the runny nose, especially outside of exercise or during specific seasons, it might suggest allergic rhinitis. These symptoms point to an immune response to specific allergens. A runny nose accompanied by fever, body aches, a sore throat, or thick, discolored mucus typically indicates a cold or other viral illness.
In some instances, a persistent or severe runny nose during exercise may be due to Exercise-Induced Rhinitis (EIR), a non-allergic condition. EIR symptoms are usually confined to physical activity and can be more bothersome than typical exercise-induced nasal discharge. Consulting a healthcare professional is advisable if symptoms are severe, significantly impact exercise performance, or cause persistent discomfort. This could indicate an underlying issue or a need for specific management.
Strategies for Management
Several practical approaches can help manage a runny nose during exercise. Breathing through the nose rather than the mouth allows nasal passages to more effectively warm, humidify, and filter incoming air. Starting exercise with a gradual warm-up period can also help nasal passages adjust to increased demands. This allows the body to slowly adapt.
Using saline nasal sprays before or during exercise can help keep nasal passages moist and prevent excessive drying, which can trigger more mucus production. In cold or dry environments, wearing a scarf or balaclava over the nose and mouth can help pre-warm and pre-humidify the inhaled air. If airborne allergens are suspected triggers, exercising indoors or during times when pollen counts are lower can help minimize exposure and reduce symptoms.